Method of producing an oriented reinforced artificial sponge



Sept. 8, 1959 J. LACHICHE ETAL METHOD OF PRODUCING AN ORIENTEDREINFORCED ARTIFICIAL SPONGE Filed March 27, 1957 III/III,

//Vu/vr0/5-, JUL/EN ZACH/(HES, ANDRE OR/OL BY I Arro/e/vsv A METHOD OFPRODUCING AN ORIENTED REINFORCED ARTIFICIAL SPONGE Iulien La'chiche andAndre Oriol, Paris, France, assignors to Novacel, Paris, France, acorporation of France Application March 27, 1957, Serial No. 648,868Claims priority, application France March 29, 1956 1 Claim. (CI. 18-48)This invention relates to the production of artificial sponges and hasfor an object to provide artificial sponges having novel and improvedcharacteristics.

Artificial sponge materials are often reinforced by incorporation ofvarious types of fiber. This is particularly the case where regeneratedcellulose is concerned.

These fibers are introduced into the liquid or viscous mass beforeregeneration, polymerization or insolubilizing the material.

The fiber is a very important factor of the overall solidity of theproduct, and its influence upon solidity is governed by the type offiber, its quantity, the dimensions, the distribution thereof throughthe material, and their orientation relative to the center-point of themass.

Absence of orientation in any specific direction results in theproduction of a spongy mass of homogeneous solidity in all directions.Preferential orientation in a given direction makes the material moreresistant to compression in the plane perpendicular to the direction ofprimary orientation, greater resistance to stretching in the directionof orientation, and greater resistance to flexure in the planeperpendicular to that of orientation.

Certain special uses of these spongy materials require maximumresistance to wear in a given plane, this being the working planedetermined by the equipment or conditions of use.

The present invention provides an improved procedure for filling moldswith the plastic mass in such a manner that preferential orientation ofthe fibers in the mass is obtained before coagulation.

More specifically the method involves forcing the material to be treatedthrough a screen of specific mesh, the bars of the screen serving tocalender the material and cause orientation of the fibers in thedirection of flow, due to friction against the bars.

The fibers thus undergo preferential orientation in the direction offlow, and retain this orientation if means are provided to assure thatupon entry into the mold, the mass is completely restricted andtherefore incapable of moving in any direction other than that by whichit entered, as other motion would destroy the orientation.

The screen specification (size and form of the openings, size and formof the bars), which may be dependent upon extraneous factors, not havingto do with the results desired (for example, the viscosity of thematter), permit manipulations with greater or lesser fractions of themass being processed, and thus permit control of the degree oforientation.

Thus, a screen with small, close mesh, will cause orientation ofvirtually all the fibers, while one of coarse mesh causes only zones,larger or smaller in size, of primary orientation. As a result, thescreen must be particularly adapted to the result desired, i.e., to theeifect of orientation upon the results of employment cf the finishedspongy material.

The invention is more readily understood with the aid of the specificexamples given below, but it will be understood that these examples areby no means restric- Patented Sept. 8, 1959 2 tive, the invention beingapplicable to various modifications and adaptations.

In the drawings:

Fig. 1 is a perspective View of a mold and screen illustrating oneembodiment of the invention with the front and end wall of the moldremoved to show the construction of the parts;

Fig. 2 is a vertical section through a mold and filling mechanismillustrating a further embodiment of the invention; and v Fig. 3 is abroken perspective view of a further embodiment wherein the mold isstationary.

Referring to the drawings more in detail, a closed mold 10 is shown inFig. 1 having a top closure member 11. A screen 12 conforms generally tothe area of the mold and is mounted on a frame 13 for vertical movementin the mold to the dotted position 14 below the topclosure 11. The frame13 is raised by suitable means not shown.

The mold is filled with the sponge forming material with the screen 12in its lower position. The top closure 11 is then placed over thematerial and the frame 13 and screen 12 raised to the dotted position.This motion of the screen forces the sponge forming material through themesh of the screen 12 and orients the fibers as above described.

The mass is then retained in the mold without further movement while thesolidifying reaction takes place. The sponge thus formed will have itsfibers oriented vertically due to the calendering and friction of thescreen elements produced by the movement of the screen through theunreacted material. Conversely the screen may be positioned initially atthe top of the mass and forced downwardly therethrough if desired.

Fig. 2 illustrates an embodiment wherein the sponge forming material isfed by a screw conveyor 20 through a feed chamber 21 terminating in aflared wall 22 having an open end 23 corresponding in size to the areaof the mold 24 and provided at its open end 23 with a screen 25, similarto the screen 12 of Fig. 1. The mold 24 is mounted for limited verticalmovement in response to the pressure of the sponge forming materialagainst the pressure of supporting springs 26.

In this embodiment the sponge forming material is extruded into the mold24 through the screen 25 which serves to orient the fibers as abovedescribed. After entering the mold no further movement of the mass takesplace until the artificial sponge is removed after the solidifyingreaction. Hence the sponge contains fibers which are oriented in thevertical plane.

Fig. 3 shows an embodiment wherein an upper mold 30 having a screen 31across the bottom thereof is disposed above and in registration with alower mold 32 having a closed bottom.

The upper mold 30 is filled with the sponge forming material by anysuitable means and the material is then forced by suitable pressuremeans through the screen 31 and into the lower mold 32 wherein thesolidification reaction takes place.

In this embodiment as in the previous forms, the fibers are oriented inpassing through the screen and retain their orientation during thesolidification reaction.

What is claimed is:

The method of forming artificial sponges composed of regeneratedcellulose containing reinforcing fibers which comprises extruding acellulosic sponge-forming material in the form of a viscous masscontaining randomly dispersed reinforcing fibers into a mold of uniformcross sectional area, passing through said mass while in a form havingthe cross sectional area of said mold a screen extending entirely acrosssaid area, said screen having a mesh to reorient said fibers whilepassing therethrough 3 into the direction of said passage and tocalendar the mass of cellulosic material, subjecting said mass to asolidifying reaction after passage of said screen therethrough, wherebythe fibers retain their orientation in the solidified sponge.

Shrady June 30, 1896 Morrison Nov. 3, 1896 4 Alexander Aug. 29, 1905Riesch Dec. 19, 1911 Wyatt et al. May 1, 1934 Frendenberg et al Apr. 12,1938 Vantier May 10, 1938 Holzapfel Nov. 1, 1938 Braker June 13, 1939Banigan et a1 Apr. 14, 1942 Saint Dani's June 20, 1950 Fisch June 29,1954 Seipt Aug. 23, 1955'

